package twoPointers;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;

public class threenums {
    public List<List<Integer>> threeSum(int[] nums) {

        Arrays.sort(nums);
        int n=nums.length;
        List<List<Integer>> cur=new LinkedList<>();
        for(int i=0;i<n;){
            if(nums[i]>0)break;
            int left=i+1,right=n-1,target=-nums[i];
            while(left<right){
                int sum=nums[left]+nums[right];
                if(sum>target) right--;
                else if(sum<target) left++;
                else{
                    cur.add(new ArrayList<Integer>(Arrays.asList(nums[i],nums[left],nums[right])));
                    left++;
                    right--;
                    while(left<right&&nums[left]==nums[left-1])left++;
                    while(left<right&&nums[right]==nums[right+1])right--;
                }

            }
            i++;
            while(i<n&&nums[i]==nums[i-1]){
                i++;
            }
        }
        return cur;
    }
}
